Answer:
(A) It will take 22 sec to come in rest
(b) Work done for coming in rest will be 0.2131 J
Explanation:
We have given the player turntable initially rotating at speed of 
Now speed is reduced by 75 %
So final speed 
Time t = 5.5 sec
From first equation of motion we know that '

(a) Now final velocity 
So time t to come in rest 
(b) The work done in coming rest is given by

The final temperature of the system is 32.5°
we know, H = mcT
where, H = Heat content of the body
m = Mass,
c = Specific heat
T = Change in temperature
According to to the Principle of Calorimetry
The net heat remains constant i.e.
⇒ the heat given by water = heat accepted by the aluminum container.
⇒ 330 x 1 x (45 - T) = 855 x

x (T - 10)
⇒ 14,850 - 330T = 183.21T - 1832
⇒ - 513.21 T = - 16682
or T = 32.5°
you would multiply 30 by 15. because its the weight times the distance.
Answer:
0.17 s
Explanation:
Given:
Δy = 0.15 m
v₀ = 0 m/s
a = 9.8 m/s²
Find: t
Δy = v₀ t + ½ at²
0.15 m = (0 m/s) t + ½ (9.8 m/s²) t²
t = 0.17 s
Answer:
There is an interval of 24.28s in which the rocket is above the ground.
Explanation:





From Kinematics, the position
as a function of time when the engine still works will be:

At what time the altitud will be
?
⇒ 
Using the quadratic formula:
.
How much time does it take for the rocket to touch the ground? No the function of position is:

Where our new initial position is
, the velocity when the engine breaks is
and the only acceleration comes from gravity (which points down).
Now, when the rocket tounches the ground:
Again, using the quadratic ecuation:

Now, the total time from the moment it takes off and the moment it tounches the ground will be:
.